Improvement in manufacture of paper



J. O. GREGG. Manufacture of Paper.

No, 211,991. Patented Feb. 4,1879

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UNI ED STATES PATENT nron.

JOSEPH O. GREGG, OF ELKHART, INDIANA.

IMPROVEMENT IN MANUFACTURE OF PAPER.

Specification forming part of Letters Patent No. 2 11,991, datedFebruary 4, 1879; application filed 1 January 4, 1879."

To all whom it may concern: I

Be it known that I, JOsEPH O. GREGG, of Elkhart, Indiana, have inventedan Improvement in the Manufacture of Paper, of which dry or partiallydry sheet of paper, as it comes fromthemaking-cylinder,thefinishing-surface, formed also directly from thepulp.

It consists, also, in an apparatus for applying this process.

' Heretofore, in the manufacture of paper of this class,it has beencustomary either to apply the finishing-pulp directly to the coarser orboard pulp upon the wet felt, or to form the board or paper of thecoarser material and afterward paste the finishing-paper thereto.

The latter process is expensive, and in the former the directapplication of the pulp to form the finishing to the wet paper upon thefelt caused the finishing-sheet to be soiled by the dark and dirty waterabsorbed from the dark paper and the felt that carried it.

In carrying out my process I use but one felt. This takes up the darkcoarse pulp from the vats, in the usual way. Before, however, it iscarried to the making-cylinder by which the finishing-pulp is applied,the felt is cleaned, and the paper or board formed from the dark pulp isdried, or partially dried, by any means suitable for the purpose. Afterthis has been done, no water remains, either in the newlyformed sheet orin the felt, by which the white or finishing pulp could be soiled. Thelatter pulp is then applied directly by the makingcylinder to the boardor paper.

In order to facilitate the cleaning and drying of the felt and the darksheet they are separated after leaving the making-cylinder, and,preferably, passing through wet-presses, the wet felt being carried overguide-rolls and between squeezing-rolls, and either washed and pressed,or simply pressed. Thence it is returned to the cylinder which appliesthe finishing-pulp. It there meets the paper or board brought directlyfrom the wet-press.

The board may have, if desired, paste applied to it after leaving thewet-press and before reaching the finishing-cylinder. I

It is essential that the sheet, when it reaches the cylinder by whichthe finishing-pulp is applied, should be partially or entirely dry, soas to be free from any dirty water which would soil the facing. Thesteps which I have found to be most advantageous forsecuring this objectare, first, that ,the felt, after it has taken up the coarse dark pulpwhich forms the body of thepaper orboard, shouldpass through thewetpress; next, that the felt should be separated from the sheet andpassed through pressing or'washing and pressing apparatus before itreaches the cylinder for the application of the finishing-pulp. It mayreturn to the dark sheet at or before the point of its contact with thenext cylinder.

"The application of the paste-to the dark sheet before it reaches thefinishing-cylinder may be used with good effect; but it is notessential, as the wet finishing-pulp will adhere to the dark sheet,thelatter being moist enough for the purpose without containing anysuperfluous water to discolor the white finish.

In the drawing hereunto attached I have shown in vertical longitudinalsection an apparatus adapted to carry out my invention. In thisdrawing,A A represent ordinary makingcylinders, revolving in propervats, in the usual manner. Over these is carried the felt, (shown indotted lines.) The dark coarse sheet of ordinary straw pulp, or otherdark coarse material, is formed on the cylinders, and taken up by thewet felt, in the usual manner. A wet press at D D is located next inorder after the making-cylinderAA. Thefeltpassesthrough this press, andthe dark sheet is pressed on the under side of the felt. At this point,and after leaving the press, the wet felt is separated from the darksheet, and passes upward over a guide-roll, H. Between the guide-rolls Hand L is shown a trough, I, in which are located the squeeze-rolls K K.

A perforated pipe (shown at a) may be used, if desired, to wash the feltbefore it passes through the squeeze-rolls K K. The felt, afterbeingpressed to remove the dirty water, passes over the guide-rolls L,and returns to the dark sheet at M, at the point of contact with thenext cylinder, or alittlebeforc. To this point the dark sheet shown bythe full line X is brought directly from the wet-press D D. Apasting-cylinder, 0, may be located between the wet-press D D and thecylinder A, which applies the finishing-pulp. This paste-roll revolvesin an ordinary paste-vat, and the sheet may be caused gently to touchthe surface by the roll R.

From the making-cylinder A the finished sheet may be carried upon thefelt, over suitable guides, to a wet-press, E, after which the sheet isseparated from the felt and carried over suitable steam-driers. The feltreturns over proper guides, through suitable washing apparatus S, to themaking-cylinder A.

The finishing-pulp is firmly united to the dark sheet by the action ofthe press E; but as the dirty water had been extracted from the felt andthe dark sheet previous to the application of the finishing-pulp, therecan be no stain upon the finished paper.

In forming the paper or board by my improved process, I use for the bodyof the paper, or for one side, ordinary straw-pulp, or other coarse darkmaterial. For the other side, which constitutes the face of the papenIuse clear, or substantially elear,w0od-pu1p.

Having thus described my invention, what 7 I claim, and desire to secureby Letters 'Patent of the United States, is

1. The described process in the manufacture of paper or board,consisting, first, in forming the dark coarse sheet, then drying, orpartially drying, the same and cleaning the felt, and subsequentlyapplying the wet finishing-pulp, as set forth.

2. In the manufacture of paper of the described class, the process offirst forming the dark sheet upon the felt, then passing it through awet-press, and subsequently separatingthefelt'from the sheet andcleaning the said felt, and returning it to'the said sheet at or nearthe point of contact with the cylinder for application of thefinishing-pulp, as set forth.

3. An apparatus for forming paper of the described class, consisting ofan endless felt, of a making cylinder or cylinders for the dark pulp, ofa making cylinder or cylinders for the finishing-pulp, and ofintermediate inech auism for cleanin the felt, the parts being combinedand operating asset forth.

4. An apparatus formaking paper of the described class, :onsistin-g ofan endless felt, of the making-cylinders A, wet pressrolls D D, guide-rolls, and intermediate squeezingrolls, with or without a washing-pipe,and of a cylinder, A, the parts being adapted to operate in the mannerset forth.

In testimony whereof I havesigned my name to this specification in thepresence of two subscribing witnesses. p

JOSEPH'O. GREGG.

Witnesses

